Obesity is a difficult to treat chronic condition defined by a body mass index (BMI=mass/height2 [kg/m2]) greater than 30. For obese persons, excessive weight is commonly associated with increased risk of cardiovascular disease, diabetes, degenerative arthritis, endocrine and pulmonary abnormalities, gallbladder disease and hypertension. Additionally, such persons are highly likely to experience psychological difficulties because of lifestyle restrictions such as reduced mobility and physical capacity, due to back pain, joint problems, and shortness of breath. In severe cases, this can contribute to absenteeism and unemployment. Moreover, impairment of body image can lead to significant psychological disturbances. Repeated failures of dieting and exercise to resolve the problem of obesity can result in feelings of despair and the development of clinical depression.
Bariatric surgery is often recommended for persons suffering from morbid obesity. Preferably, the invasive treatment is accompanied by changes in lifestyle, such as improved regulation of eating habits and an appropriate exercise regimen. Such lifestyle changes are dependent upon the self-discipline and cooperation of the patient. Policker S et al., in an article entitled, “Electrical Stimulation of the Gut for the Treatment of Type 2 Diabetes: The Role of Automatic Eating Detection,” J Diabetes Sci and Technol 2(5):906-912 (2008), relevant portions of which are incorporated herein by reference, review the performance of an automatic eating detection device that continuously senses changes in tissue impedance and initiates treatment sessions upon detection of eating.
PCT Patent Publication WO 02/082968 to Policker et al., relevant portions of which are incorporated herein by reference, describes apparatus and methods for detecting the occurrence of an eating event by a subject and analyzing the quantity and characteristics of the food ingested.
PCT Publication WO 06/018851 to Kliger et al., relevant portions of which are incorporated herein by reference, describes gastric apparatus including one or more sensors adapted to generate respective sensor signals responsive to activity of a gastrointestinal tract of a subject. A control unit is adapted to receive and analyze the sensor signals and to determine that an eating event has occurred, responsive to at least one of the sensor signals and a threshold. The control unit identifies an aspect of at least one of the sensor signals deriving from rhythmic activity of the gastrointestinal tract that is not indicative of current eating by the subject, and modifies the threshold responsive to the aspect of the signals that derives from activity that is not indicative of current eating.
U.S. Pat. No. 6,104,955 to Bourgeois, relevant portions of which are incorporated herein by reference, describes a method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus comprises an implantable pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads are coupled to the circular layer of the stomach. The pulse generator preferably comprises sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions are occurring. One embodiment detects gastric arrhythmias by periodically reverting into a sensed intrinsic gastric rhythm mode. In this mode the output of electrical stimulation is adjusted to only occur at an exceedingly slow rate. This slow rate of stimulation thus permits the gastrointestinal tissues to undergo an intrinsic depolarization so that the underlying intrinsic slow wave rate may be detected.
U.S. Pat. No. 5,995,872 to Bourgeois, relevant portions of which are incorporated herein by reference, describes a method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus comprises an implantable pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads are coupled to the circular layer of the stomach. The pulse generator preferably comprises sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions are occurring. In particular two sensors are included. The first sensor senses low frequency gastrointestinal electrical activity between the frequency of 0.017-0.25 Hz and the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, which occurs upon normal peristaltic contractions. The second sensor only senses for a preset period after low frequency gastrointestinal electrical activity has been sensed by the first sensor. The pulse generator further delivers stimulation pulse trains to the gastrointestinal tract at a period of time after low frequency gastrointestinal electrical activity has been sensed by the first sensor. If, however, the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, then the delivery of stimulation pulse trains to the gastrointestinal tract is inhibited. In such a manner the present invention detects the occurrence of normal peristaltic contractions and further provides electrical stimulation to the gastrointestinal tract if such normal peristaltic contractions are not detected.
The following patents and patent application publications, relevant portions of which are incorporated herein by reference, may be of interest:
U.S. Pat. No. 5,188,104 to Wernicke et al.
U.S. Pat. No. 6,571,127 to Ben-Haim et al.
US Patent Application Publication 2006/0173238 to Warren
US Patent Application Publication 2005/0222638 to Foley et al.